Shifting handler-running methods to shared location (#1851)

* Shifting helper methods to shared location

* widening scope

src/Microsoft.SqlTools.ServiceLayer/Utility/BaseService.cs

@@ -0,0 +1,89 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using System.Threading.Tasks;
+using Microsoft.SqlTools.Hosting.Protocol;
+
+namespace Microsoft.SqlTools.ServiceLayer.Utility
+{
+    /// <summary>
+    /// Base class for services that contains helpful methods
+    /// </summary>
+    public abstract class BaseService
+    {
+        #region Runners with error handling
+
+        /// <summary>
+        /// Synchronous action with standard ResultStatus
+        /// </summary>
+        /// <param name="action"></param>
+        /// <param name="requestContext"></param>
+        /// <returns></returns>
+        public static async Task RunWithErrorHandling(Action action, RequestContext<ResultStatus> requestContext)
+        {
+            await RunWithErrorHandling(async () => await Task.Run(action), requestContext);
+        }
+
+        /// <summary>
+        /// Asynchronous action with standard ResultStatus
+        /// </summary>
+        /// <param name="action"></param>
+        /// <param name="requestContext"></param>
+        /// <returns></returns>
+        public static async Task RunWithErrorHandling(Func<Task> action, RequestContext<ResultStatus> requestContext)
+        {
+            await RunWithErrorHandling<ResultStatus>(async () =>
+            {
+                await action();
+
+                return new ResultStatus()
+                {
+                    Success = true,
+                    ErrorMessage = null
+                };
+            }, requestContext);
+        }
+
+
+        /// <summary>
+        /// Synchronous action with custom result
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="action"></param>
+        /// <param name="requestContext"></param>
+        /// <returns></returns>
+        public static async Task RunWithErrorHandling<T>(Func<T> action, RequestContext<T> requestContext) where T : ResultStatus, new()
+        {
+            await RunWithErrorHandling<T>(async () => await Task.Run(action), requestContext);
+        }
+
+        /// <summary>
+        /// Asynchronous action with custom result
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="action"></param>
+        /// <param name="requestContext"></param>
+        /// <returns></returns>
+        public static async Task RunWithErrorHandling<T>(Func<Task<T>> action, RequestContext<T> requestContext) where T : ResultStatus, new()
+        {
+            try
+            {
+                T result = await action();
+                await requestContext.SendResult(result);
+            }
+            catch (Exception ex)
+            {
+                await requestContext.SendResult(new T()
+                {
+                    Success = false,
+                    ErrorMessage = ex.Message
+                });
+            }
+        }
+
+        #endregion
+    }
+}